Radiotube



Oct. 2, 1934. J, HOZA 1,975,721

RADIOTUBE Filed July 26, 1929 /6 I INVENTOR fok?? /Vi HEI/@4% MMM.

ATTORN EY15.

Patented Oct. 2, 1934 UNITED STATES.

RADIOTUBE John Hoza, Newark, Nr J.,

Harris Company, of New Jersey assignor to .Drivern, N., J., a corporation Application July 26, 1929, Serial No. 381,112

. comms.

My invention relates to tubes for radio receiving sets, and has special reference to anode plates for such tubes.

In tubes for receiving sets that are operated by batteries, the anode plate is commonly made up of two rectangular pieces of sheet nickel or similar metal which are secured at their vertical edges to the usual support wires, the portions of the plates between the support wires being spaced at opposite sides of the grid and the heating element or cathode of the tube. In the case, however, of tubes for receiving sets that are operated from an alternating current power supply, it has been found that sheet metal plates such as used in low wattage or battery operated tubes are unsuitable owing to the fact such plates would soon become over-heated. Accordingly, in such high wattage tubes heretofore in common commercial use, the anode plate has usually been made up of wire cloth or mesh looped into cylindrical form about the grid and heating element and fastened at its ends to a support wire. While wire mesh has met with a certain amount of success because of its heat dissipating properties, it has been found unsatisfactory in many other respects. In forming the anode plate from wire mesh, a piece of mesh of suitable size is cut from a roll of wire mesh or cloth. In cutting, extreme care must be taken otherwise the piece cut out is liable to be more or less frayed and rough at the edges, making it substantially useless for the purposes intended. The elements of radio tubes of the type indicated are closely spaced and it is required that this spacing be controlled and maintained within extremely small dimensional limits. Wire mesh, however, is more or less limp and flimsy and diicult to handle, and consequently, extreme care must be exercised inshaping and supporting the mesh in the tube to insure proper spacing thereof from the grid and heating element, and the making. of suitablev electrical connections. Other disadvantages of the use of wire mesh for an anode plate are that it takes a relatively long time to heat the mesh to the required temperature during the evacuation of the tubes; the small and more or less uneven holes are liable to become clogged during the carbonizing treatment; the corners and crevices produced by the crossed wires tend to retain loose particles of the carbonizing medium which are free to drop off during the evacuation of the tube and cause short circuiting; and the crossed wires result in an uneven surface being presented to the grid and cathode and, consequently, uneven spacing of the mesh from these parts of the tube.

(Cl. Z50-27.5)

The principal object of the present invention is to provide an anode plate for high wattage radio tubes of the type indicated which overcomes the disadvantages of the wire mesh as above described, while retaining all of the advantages.

With this and other objects in vew, the features of the invention will be readily understood from the following description and accompanying drawing, in which:

Figure 1 is a side view of a tube for radio receiving sets provided with my improved anode plate in its preferred form;

Fig. 2 is a sectional view on an enlarged scale taken on the line 2-2 of Fig. 1;

Fig. 3 is a plan View of a portion of a perforated strip ready to be cut to form the parts of my improved anode plate;

Fig. 4 is a, side view of one of the parts of my improved plate; and

Fig. 5 is a similar view of a slightly modified form.

The radio tube illustrated in Figs. 1 and 2-of v the drawing is provided with the usual bulb 2, a glass press or stem 4, heating or cathode element 6, grid wires 8, support wires 10 for the grid, and support wires 12 for the anode plate.

In accordance with my invention, the anode plate may be made in two rectangular parts 14 which have their vertical edges brought together and spot-welded or otherwise secured to the support wires 12. The portions of the two parts of the plate between the support wires are arranged parallel tol and equally spaced from the grid 8 and the plane of the cathode 6. These portions of the parts of the plate are provided with perforations 16. The margin of each part is preferably unperforated so as ,to permit the unperforated vertical edges to be easily secured to the support wires, and the unperforated upper and lower edges of each part to serve to reinforce the part and provide smooth edges.

I have found that satisfactory results may be secured in the case of the ordinary tube by making the parts of the anode of nickel or similar metal of substantially .006 of an inch in thickness and with the perforations substantially .05 of an inch in diameter with substantially twohundred and twenty-five perforations to the square inch. The parts of the anode may be formed from a strip 18 perforated as shown, the strip being cut on lines 20 to form said parts. If desired each part of the anode may have stiffening ribs or beads 22 (Fig. 5), this being especially desirable where the parts are formed from exceptionally thin and pliable metal.

anodeV being maintained at a'suitably low teinperature. The parts of the anode maybe made su'iciently' rigidso as not to becoine easily distorted 'by accidental shock or jar, or after long periods of use, thus insuring proper spacing Ybeing maintained. The anode parts present smooth surfaces to the grid and cathode so that :all points are equally spacedwirom the grid and uniform reception of the electron emission from the cathode is insured. The .parts mayl be so connected to the'support wires as to provide direct electrical Contact throughout their vertical edges, and the structure of the perforated parts, unlike a wire mesh, ensures uniform potential being maintained throughout their areas duringY the operation of the tube.

- Ithas been found that my improved perforated sheet metal anode may be heated to the required temperature during the evacuation of the tube 1 much more quickly thany Vwhere a wire mesh is employed, and thus a great saving of time in the manufactiire of the tubes is eiected. Moreover, where the perforated metal sheet is employed, the tube is more easily freed of gases, the exposed surfaces Ybeing of less area. vIn carbonizing the strip from which the parts are made, it has been found that there is nol danger Yci the perforations becoming clogged, and-moreover there are no corners or crevices in which loose particles o the carbonizing medium are likely to lodge so asY to drop off during the evacuation of the tube.

it will be apparent that while onlyone construction and form of my improved anode is shown in the drawing, it may be made of various forms and shapes, and thel perforations formed of various sizes and arrangements to meet different requirements. It will also be apparent that my invention permits various other modications to be made without departing from the spirit thereof or the scopeof the appended claims.

What I claim is:

l. A tube for radio receiving sets having,av

glass bulb, a cathode, a grid, and an anode comprising a piece of sheet nickel or similar metal of substantially six thousandths of an inch thickness and having the portion thereof opposite to said cathode and grid provided with perforations of substantially fifty thousandths of an inch in diameter and two hundred tWenty-ilve perforations to the square inch, substantially theentire area of the outer surface of the perforated sheet metal being in direct heat radiating relation to the glass bulb.

Lavar/ai 2.a tube for radio receiving sets, having a glass bulb, a cathode, and an electrode coinprising perforated sheet metal surrounding the cathode, substantially the entire area of the outer surface ci' the perforated sheet metal be ing in direct heat radiating relationV to the glass bulb, the perforations being of small size and closely spaced and-there being several hundred perforations to the square inch. i

' 3. A tube for radio receiving sets having a glass bulb, a cathode, a grid element and an anode element, one of said elements comprising a piece of sheet nickel or similar metal of not over six thousandths ci an k.inch in thickness and havperforated sheet metal being in direct heat rae diating relation to the glass bulb.

Ll. A tube for radio receiving sets having, a glass bulb, a cathode, a grid, and an anode comprising a piece of sheet metal provided with several hundred perforations to the square inch arranged opposite to said grid y,and cathode, substantially the entire area ofthe outer surface of the. perforated sheet metal being in direct heat 'radiating' relation tothe glass bulb, said perforations being of small size and closely spaced.

5. A tube for radid receiving sets having a glass bulb, and a plurality of electrodes including a cathode, ,a control grid, and an electrode surrounding all of the other electrodes and made of perforated sheet metal with substantially the entire area of the outer surface of the perforated` ing thel portion thereof opposite to said cathode l les zit

small size and closely spaced and there being ll5 several hundred perforations to the square inch.

den electrode for an electron tube for a radio receivinnr set, said tube being of the type`having a glass bulb and a plurality of electrodes including a cathode'and a control grid, said rst mentioned electrode'being adapted to surround all of the other electrodes with its outer surface in direct heat 'radiating relation with the glass bulb, and being made of perforated sheet metal,

said metal being'ot nickel or similar metal ofthe order of six thousandths of an inch in thicknesswith the perforations of the order of if,ty

l thousandths of an inch in width and of the order of two hundred and twenty-live perforations to' the square inch. A

JOHN HOZA. 

